Touch and hover switching

ABSTRACT

Touch and hover switching is disclosed. A touch and hover sensing device can switch between a touch mode and a hover mode. During a touch mode, the device can be switched to sense one or more objects touching the device. During a hover mode, the device can be switched to sense one or more objects hovering over the device. The device can include a panel having multiple sensors for sensing a touching object and/or a hovering object and a touch and hover control system for switching the device between the touch and hover modes. The device&#39;s touch and hover control system can include a touch sensing circuit for coupling to the sensors to measure a capacitance indicative of a touching object during the touch mode, a hover sensing circuit for coupling to the sensors to measure a capacitance indicative of a hovering object during the hover mode, and a switching mechanism for switching the sensors to couple to either the touch sensing circuit or the hover sensing circuit. The device can switch modes based on a condition of the device, such as an expiration of a timer or a relative distance of an object from the panel.

CROSS REFERENCE TO RELATED APPLICATION

This application claims benefit of U.S. Provisional Application No.61/377,829, filed Aug. 27, 2010, the contents of which are incorporatedby reference herein in their entirety for all purposes.

FIELD

This relates generally to touch and hover sensing and more particularlyto devices that can perform both touch and hover sensing.

BACKGROUND

Touch sensitive devices have become quite popular as input devices tocomputing systems because of their ease and versatility of operation aswell as their declining price. A touch sensitive device can include atouch sensor panel, which can be a clear panel with a touch sensitivesurface, and a display device such as a liquid crystal display (LCD)that can be positioned partially or fully behind the panel or integratedwith the panel so that the touch sensitive surface can cover at least aportion of the viewable area of the display device. The touch sensitivedevice can allow a user to perform various functions by touching thetouch sensor panel using a finger, stylus or other object at a locationoften dictated by a user interface (UI) being displayed by the displaydevice. In general, the touch sensitive device can recognize a touchevent and the position of the touch event on the touch sensor panel, andthe computing system can then interpret the touch event in accordancewith the display appearing at the time of the touch event, andthereafter can perform one or more actions based on the touch event.

Some touch sensitive devices can also recognize a hover event, i.e., anobject near but not touching the touch sensor panel, and the position ofthe hover event at the panel. The touch sensitive device can thenprocess the hover event in a manner similar to that for a touch event,where the computing system can interpret the hover event in accordingwith the display appearing at the time of the hover event, andthereafter can perform one or more actions based on the hover event.

While touch and hover capabilities in a touch sensitive device aredesirable, together they can present a challenge to cooperativeperformance for accurate, reliable detection of touch and hover events.

SUMMARY

This relates to switching a touch and hover sensing device between atouch mode and a hover mode. During a touch mode, the device can beswitched to sense one or more objects touching the device. During ahover mode, the device can be switched to sense one or more objectshovering over the device. The device can include a panel having multiplesensors for sensing a touching object and/or a hovering object and atouch and hover control system for switching the device between thetouch and hover modes. The device's touch and hover control system caninclude a touch sensing circuit for coupling to the sensors to measure acapacitance indicative of a touching object during the touch mode, ahover sensing circuit for coupling to the sensors to measure acapacitance indicative of a hovering object during the hover mode, and aswitching mechanism for switching the sensors to couple to either thetouch sensing circuit or the hover sensing circuit. The device canswitch modes based on a condition of the device, such as an expirationof a timer or a relative distance of an object from the panel. Thisswitching can advantageously provide improved touch and hover sensing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an exemplary touch and hover sensing device accordingto various embodiments.

FIG. 2 illustrates an exemplary touch and hover sensing device sensing atouch proximate thereto that can be compensated for according to variousembodiments.

FIG. 3 illustrates an exemplary touch and hover sensing device that cancompensate for a touch signal according to various embodiments.

FIG. 4 illustrates an exemplary method to compensate for a touch signalin a touch and hover sensing device according to various embodiments.

FIG. 5 illustrates another exemplary method to compensate for a touchsignal in a touch and hover sensing device according to variousembodiments.

FIG. 6 illustrates another exemplary touch and hover sensing device thatcan compensate for a touch signal according to various embodiments.

FIG. 7 illustrates another exemplary method to compensate for a touchsignal in a touch and hover sensing device according to variousembodiments.

FIG. 8 illustrates another exemplary method to compensate for a touchsignal in a touch and hover sensing device according to variousembodiments.

FIG. 9 illustrates an exemplary touch and hover sensing device sensingan object proximate thereto that can be shape profiled according tovarious embodiments.

FIG. 10 illustrates an exemplary method to profile an object shape in atouch and hover sensing device according to various embodiments.

FIG. 11 illustrates another exemplary method to profile an object shapein a touch and hover sensing device according to various embodiments.

FIG. 12 illustrates another exemplary method to profile an object shapein a touch and hover sensing device according to various embodiments.

FIG. 13 illustrates an exemplary touch and hover sensing device sensinga small close object and a large distant object that can bedifferentiated from each other according to various embodiments.

FIG. 14 illustrates an exemplary touch and hover sensing device that candifferentiate between a small close object and a large distant objectaccording to various embodiments.

FIG. 15 illustrates another exemplary touch and hover sensing devicethat can differentiate between a small close object and a large distantobject according to various embodiments.

FIG. 16 illustrates an exemplary method to differentiate between a smallclose object and a large distant object in a touch and hover sensingdevice according to various embodiments.

FIG. 17 illustrates an exemplary touch and hover sensing device sensingconcurrently touching and hovering objects according to variousembodiments.

FIG. 18 illustrates an exemplary touch and hover sensing device that canconcurrently sense a touching object and a hovering object according tovarious embodiments.

FIG. 19 illustrates an exemplary method to concurrently sense a touchingobject and a hovering object in a touch and hover sensing deviceaccording to various embodiments.

FIG. 20 illustrates another exemplary method to concurrently sense atouching object and a hovering object in a touch and hover sensingdevice according to various embodiments.

FIG. 21 illustrates an exemplary touch and hover sensing device sensingmultiple hovering objects according to various embodiments.

FIG. 22 illustrates an exemplary graph depicting capacitance measurementversus sensor position in a touch and hover sensing device according tovarious embodiments.

FIG. 23 illustrates an exemplary method to sense multiple hoveringobjects in a touch and hover sensing device according to variousembodiments.

FIG. 24 illustrates an exemplary touch and hover sensing device that cancompensate for signal drift according to various embodiments.

FIG. 25 illustrates another exemplary touch and hover sensing devicethat can compensate for signal drift according to various embodiments.

FIG. 26 illustrates an exemplary touch and hover sensing devicecompensating for signal shift according to various embodiments.

FIG. 27 illustrates an exemplary method to compensate for signal driftin a touch and hover sensing device according to various embodiments.

FIG. 28 illustrates an exemplary touch and hover sensing device that cancompensate for sensor resistance according to various embodiments.

FIG. 29 illustrates another exemplary touch and hover sensing devicethat can compensate for sensor resistance according to variousembodiments

FIG. 30 illustrates another exemplary touch and hover sensing devicethat can compensate for sensor resistance according to variousembodiments

FIG. 31 illustrates another exemplary touch and hover sensing devicethat can compensate for sensor resistance according to variousembodiments.

FIG. 32 illustrates an exemplary graph depicting capacitance variationversus sensor location in a touch and hover sensing device according tovarious embodiments.

FIG. 33 illustrates a graph depicting compensation for capacitancevariation versus sensor location in a touch and hover sensing deviceaccording to various embodiments.

FIG. 34 illustrates an exemplary method to compensate for capacitancevariation as a function of location in a touch and hover sensing deviceaccording to various embodiments.

FIG. 35 illustrates an exemplary touch and hover sensing device that canswitch between touch and hover modes according to various embodiments.

FIG. 36 illustrates another exemplary touch and hover sensing devicethat can switch between touch and hover modes according to variousembodiments.

FIG. 37 illustrates another exemplary touch and hover sensing devicethat can switch between touch and hover modes according to variousembodiments.

FIG. 38 illustrates another exemplary touch and hover sensing devicethat can switch between touch and hover modes according to variousembodiments.

FIG. 39 illustrates an exemplary method to switch between touch andhover modes according to various embodiments.

FIG. 40 illustrates another exemplary method to switch between touch andhover modes according to various embodiments.

FIG. 41 illustrates an exemplary touch and hover sensing device having agrounding shield to minimize interference from the device display at thedevice touch and hover panel according to various embodiments.

FIG. 42 illustrates an exemplary touch and hover sensing device that canminimize interference from the device display at the device touch andsensor panel by providing an optimal distance therebetween according tovarious embodiments.

FIG. 43 illustrates an exemplary computing system that can perform touchand hover sensing according to various embodiments.

FIG. 44 illustrates an exemplary mobile telephone that can perform touchand hover sensing according to various embodiments.

FIG. 45 illustrates an exemplary digital media player that can performtouch and hover sensing according to various embodiments.

FIG. 46 illustrates an exemplary computer that can perform touch andhover sensing according to various embodiments.

DETAILED DESCRIPTION

In the following description of various embodiments, reference is madeto the accompanying drawings which form a part hereof, and in which itis shown by way of illustration specific embodiments which can bepracticed. It is to be understood that other embodiments can be used andstructural changes can be made without departing from the scope of thevarious embodiments.

This relates to improved touch and hover sensing. Various aspects oftouch and hover sensing can be addressed to improve detection of touchand hover events. In some embodiments, a touch and hover sensing devicecan ensure that a desired hover event is not masked by an incidentaltouch event, e.g., a hand holding the device, by compensating for thetouch event in the sensing signal that represents both events.Conversely, in some embodiments, when both the hover and touch eventsare desired, the device can make adjustments to its sensors and/or thesensing signal to ensure that both events are detected. In someembodiments, the device can improve the accuracy of its determination ofthe device user interface location to which a hovering object ispointing by profiling the object shape. In some embodiments, the devicecan differentiate between object distance and area (or size) so as toproperly process the corresponding sensing signal and subsequentlyperform the intended actions. In some embodiments, the device canimprove detection of concurrent hover events. In some embodiments, thedevice can compensate for signal drift in the sensing signal byadjusting the baseline capacitance of the device. In some embodiments,the device can compensate for resistance from the touch and hoversensors by making adjustments to the sensors and/or the voltage patternsdriving the device. In some embodiments, the device can compensate thesensing signal for sensitivity variations of the sensors (generally atissue during a hover event), by applying a gain factor as a function ofthe location of the hover event to the sensing signal. In someembodiments, the device can improve sensor switching between a touchmode and a hover mode by compensating for parasitic capacitanceintroduced by the switching components in the sensing signal. In someembodiments, the device can improve integration of a display with thesensors by reducing interference from the display at the sensors.

These and other approaches can advantageously provide improved touch andhover sensing.

FIG. 1 illustrates an exemplary touch and hover sensing device accordingto various embodiments. In the example of FIG. 1, which is drawnsymbolically, touch and hover sensing device 100 can include sensorpanel 111 having an array of horizontal lines 101 and vertical lines 102that can cross over each other to form sensors for sensing a touchingobject and/or a hovering object. Alternatively, the horizontal lines 101and the vertical lines 102 can be arranged near each other on the samelayer without making direct electrical contact to form the sensors.Other non-orthogonal arrangements of the lines 101, 102 can also beemployed based on the needs of the device 100. The horizontal lines 101and the vertical lines 102 can be electrically conductive traces ofconductive material, e.g., indium-tin-oxide (ITO). The conductivematerial can be transparent, semi-transparent, or opaque depending onthe needs of the device 100. The touch and sensing device 100 can alsoinclude touch and hover control system 107 that can drive the sensorpanel 111 with electrical signals, e.g., AC signals, applied to thehorizontal lines 101 and/or the vertical lines 102. The AC signalstransmitted to the sensor panel 111 can create electric fields extendingfrom the sensor panel, which can be used to sense objects hovering overor touching on the panel. The touch and hover control system 107 canthen measure the change in capacitance caused by the hovering ortouching objects on the horizontal lines 101 and/or the vertical lines102 to detect a hover event or a touch event at the sensor panel 111.

The touch and hover sensing device 100 can operate based on selfcapacitance and/or mutual capacitance. In self capacitance, the selfcapacitance of the sensor panel 111 can be measured relative to somereference, e.g., ground. An object placed in the electric field near thesensor panel 111 can cause a change in the self capacitance of thesensor panel, which can be measured by various techniques. For example,the touch and hover control system 107 can drive each horizontal line101 and vertical line 102 to create an electric field extending from thesensor panel 111. The touch and hover control system 107 can thenmeasure the self capacitance on each horizontal line 101 and verticalline 102, where the strongest measurements, e.g., the greatest changesin self capacitance, on the horizontal lines and the vertical lines canindicate the (x,y) location of a hover event or a touch event.

In mutual capacitance, the mutual capacitance of the sensor panel 111can be formed between the crossing or proximate horizontal and verticallines 101, 102. An object placed in the electric field near the sensorpanel 111 can cause a change in the mutual capacitance of the sensorpanel, which can be measured by various techniques. For example, thetouch and hover control system 107 can drive each horizontal line 101 tocreate an electric field extending from the sensor panel 111. The touchand hover control system 107 can then measure the change in mutualcapacitance on the vertical lines 102, where the strongest measurements,e.g., the greatest changes in mutual capacitance, at the crossings orproximate locations of the horizontal and vertical lines can indicatethe (x,y) location of a hover event or a touch event.

In some embodiments, the touch and hover sensing device 100 can use selfcapacitance to detect a hover event and mutual capacitance to detect atouch event. In other embodiments, the device 100 can use selfcapacitance to detect all events. In still other embodiments, the devicecan use mutual capacitance to detect all events. Various capacitanceconfigurations can be used according to the needs of the device.

As described herein, in some embodiments, a capacitance measurement canindicate an absolute capacitance and, in some embodiments, a capacitancemeasurement can indicate a change in capacitance.

Below are various aspects of touch and hover sensing that can beaddressed to provide improved detection of touch and hover eventsaccording to various embodiments.

Touch Signal Compensation

An object touching a sensing device can generally produce a strongersignal than an object hovering over the device, such that the touchsignal can mask or otherwise reduce detectability of the hover signalwhen they occur at the same time. This can be particularly problematicwhen the touch signal is merely incidental and the hover signal is ofinterest. FIG. 2 illustrates such an example. Here, a user can grasptouch and hover sensing device 200 with left hand 212, where thumb 212-atouches the device sensing area, and at the same time hover over thedevice with right hand 214, where finger 214-b points to areas on thedevice's UI display to cause some action. Because the thumb 212-atouches the device 200, the sensors proximate to the thumb can generatea stronger signal, in some cases, a saturated signal. In contrast,because the finger 214-b hovers above the device 200, the sensorsdetecting the finger can generate a weaker signal, in some cases, a muchweaker signal. To properly recover the weaker hover signal, the device200 can compensate for the effects of the stronger touch signal.

FIG. 3 illustrates an exemplary touch and hover sensing device that cancompensate for a touch signal according to various embodiments. In theexample of FIG. 3, sensors formed by sensor lines 301, 302 in touch andhover sensing device 300 can be partitioned (symbolically illustrated bybroken lines) into quadrants 300-a, 300-b, 300-c, and 300-d such thatthe sensing signals associated with the sensors in these quadrants canalso be partitioned. The quadrants having stronger touch signals can bedetected and separated from the quadrants having weaker hover signals,such that the weaker hover signals can be recovered for furtherprocessing and the stronger touch signals can be ignored or discarded.In some embodiments, the partitioning can be performed in softwareand/or firmware, where the quadrants can share sensor lines 301, 302. Insome alternate embodiments, the partitioning can be done in hardware,where each quadrant can have separate sensor lines 301, 302.

Although the touch and hover sensing device of FIG. 3 is partitionedinto quadrants, other numbers of partitions and/or configurations arealso available provided that each partition includes at least one edgeof the device for connecting the sensor lines to drive and sensecircuitry.

FIG. 4 illustrates an exemplary method to compensate for a touch signalin the touch and hover sensing device of FIG. 3. In the example of FIG.4, the capacitance in each partition can be measured (410). Adetermination can be made whether the capacitance measurement exceeds apredetermined threshold (420). If the measurement exceeds the threshold,indicative of a strong or saturated signal, then the capacitancemeasurement can be ignored as an incidental touch signal, e.g., a thumbholding the device (430). Otherwise, if the measurement does not exceedthe threshold, indicative of a weaker signal, then the capacitancemeasurement can be retained for further processing as a desired hoversignal, e.g., a finger hovering over the device (440).

FIG. 5 illustrates another exemplary method to compensate for a touchsignal in the touch and hover sensing device of FIG. 3. In the exampleof FIG. 5, the device sensor lines can be driven with a specific voltageso as to ensure that a touch saturates the associated sensors formed bythe sensor lines (505). In some embodiments, where the sensors arepartitioned in software and/or firmware, the drive voltage to all thepartitions can be the same. In some alternate embodiments, where thesensors are partitioned in hardware, the drive voltage in partitions inwhich an incidental touch is more likely to occur can be the specificvoltage so as to saturate the sensors in those partitions, whereas thedrive voltage in the remaining partitions can be different so as toproperly sense a finger hovering over the device. The capacitance ineach partition can be measured (510). A determination can be madewhether the capacitance measurement exceeds a predetermined threshold(520). If so, indicative of a saturated signal, then the capacitancemeasurement can be ignored as an incidental touch signal (530). If not,then the capacitance measurement can be retained for further processingas a desired hover signal (540).

FIG. 6 illustrates another exemplary touch and sensing device that cancompensate for a touch signal according to various embodiments. In theexample of FIG. 6, touch and hover sensing device 600 can includegrounding shield 610 around the border of the device. In many cases, themost likely incidental touch comes from a thumb or other object graspingthe device 600 at the edges. As such, the grounding shield 610 aroundthe border can block the thumb or other object from contacting thedevice sensors formed by sensor lines 601, 602 and a touch signal beinggenerated therefrom. The grounding shield 610 can be any conductivematerial coupled to ground to shunt any capacitance from the touchingobject to ground rather than into the device sensors.

In addition or alternative to partitioning the device as in FIG. 3 orproviding a grounding shield as in FIG. 6, the drive voltageconfiguration of the device can be manipulated to compensate for a touchsignal, as described in FIG. 7.

FIG. 7 illustrates an exemplary method to compensate for a touch signalin a touch and hover sensing device by adjusting the frequency of thedrive voltage according to various embodiments. Due to resistance fromthe sensor lines' conductive material, the ability of a drive voltage totravel along a sensor line can be influenced by the drive voltage'sfrequency, where higher frequencies can be more adversely affected bythe sensor lines' resistance than lower frequencies. As a result, athigher frequency drive voltages, the sensors at the start of the sensorlines can see stronger drive voltages than sensors at the end of thesensor lines, thereby generating stronger electric fields and subsequentstronger touch and hover signals. At lower frequency drive voltages, thesensors all along the sensor lines can be driven similarly, therebygenerating acceptable electric fields and subsequent touch and hoversignals everywhere. This effect of sensor resistance on drive voltagefrequencies can be used to compensate for a touch signal.

In the example of FIG. 7, the sensor lines can be driven with a higherfrequency drive voltage (710). The capacitance at the sensors formed bythe sensor lines can be measured (720). The sensor lines can then bedriven with a lower frequency drive voltage (730). The capacitance atthe sensors can again be measured (740). Assuming that an incidentaltouch is more likely to occur at the start of the sensor lines, thehigher frequency capacitance measurements and the lower frequencycapacitance measurements can be substantially similar. Conversely,assuming that a desired hover is more likely to occur away from thestart of the sensor lines, the higher frequency capacitance measurementsand the lower frequency capacitance measurements can be substantiallydifferent, the lower frequency capacitance measurements being higher.Accordingly, the higher frequency measurements can be subtracted fromthe lower frequency measurements, thereby substantially eliminating theincidental touch signals and retaining the desired hover signals (750).

FIG. 8 illustrates another exemplary method to compensate for a touchsignal in a touch and hover sensing device by driving the device sensorlines from multiple directions according to various embodiments. Asdescribed above, the resistance from the sensor lines' conductivematerial can interfere with the drive voltages. By driving the sensorlines from different directions, the device can ensure acceptablesensing signals in aggregate. In the example of FIG. 8, horizontalsensor lines can alternate being driven from the right and the left(810). For example, the topmost horizontal sensor line can be drivenfrom the left, the next sensor line from the right, and so on. As such,the sensors formed by the left-driven sensor lines can generate strongersignals at the left of the device, whereas the sensors formed by theright-driven sensor lines can generate stronger signals at the right ofthe device (based on the assumption that the drive voltages are at leastsomewhat adversely affected by the sensor lines' resistance). Assumingthat an incidental touch is more likely to occur at the sensors on theleft side of the device, the capacitance measurements for the sensorsformed by the left-driven sensor lines can indicate the incidental touchsignal (820). On the other hand, assuming that a desired hover is morelikely to occur at the sensors on the right side of the device, thecapacitance measurements for the sensors formed by the right-drivensensor lines can indicate the desired hover signal (830). Accordingly,capacitance measurements from the left-driven sensors can be ignored ordiscarded (840). Alternatively, the incidental touch can be more likelyto occur at the sensors on the right side and the desired hover at thesensors on the left side. As such, capacitance measurements from theright-driven sensors can be ignored or discarded.

Although the examples of FIGS. 2 through 8 describe an incidental touchas more likely occurring at a side of the device, it is to be understoodthat other locations, e.g., the top and bottom, the center, and thelike, are also possible and readily compensated for according to variousembodiments.

Object Shape Profiling

An object hovering over a sensing device can point to an area on thedevice's UI display to cause an action. In some instances, there can bedifficulty in determining specifically where the object is pointing soas to cause the intended action. FIG. 9 illustrates such an example.Here, finger 914-b of hand 914 can hover over touch and hover sensingdevice 900, where the finger is pointing somewhere in area 928 of thedevice UI display. To help identify where within the region 928 thefinger 914-b is pointing, various methods associated with hand shapeprofiling can be used.

FIG. 10 illustrates an exemplary method to profile an object shape in atouch and hover sensing device according to various embodiments. In theexample of FIG. 10, a determination can be made as to the orientation ofa hovering object, e.g., a hand, relative to the touch and hover sensingdevice, such as the object oriented in an upright position toward anupper right or left corner or center of the device, the object orientedin a reversed position toward a lower right or left corner or center ofthe device, and so on (1010). The determination can be made by either auser inputting the object orientation or a suitable orientationalgorithm calculating the orientation based on the hover signal, forexample. The centroid of the object can be calculated (1020). Tocalculate the centroid, the sensor locations that detected the hoveringobject can be identified for determining the object area. The centroidof the object area and its corresponding sensor location can then becalculated using any suitable centroid detection algorithm. A pointercan be set at the centroid to indicate an initial estimate of where theobject is pointing (1030). The pointer location can be shifted from thecentroid location to another sensor location of the object area that ismore indicative of where the object is pointing and that is according tothe orientation of the object (1040). For example, if the object isoriented toward the upper right of the device UI display, the pointerlocation can be shifted in the upper-right direction from the sensorlocation corresponding to the centroid of the determined object area tothe upper-right sensor location of that area. Similarly, in anotherexample, if the object is oriented toward the top of the device UIdisplay, the pointer location can be shifted upward from the centroidlocation to an uppermost sensor location of the object area. Atrajectory or some other extrapolation can be made from the pointer ontothe UI display to estimate the pointed-to area (1050).

In some embodiments, when the touch and hover sensing device is held ina substantially upright pose, an accelerometer or a similar detector inthe device can be used to determine where to shift the pointer location(1040). For example, the accelerometer can detect the direction ofgravity with respect to the device. Assuming that the object pointing tothe device is right-side up and not upside down, the pointer locationcan be shifted from the centroid location to another sensor location inthe direction opposite gravity. The shifted pointer can then be used toestimate the pointed-to area on the UI display (1050).

FIG. 11 illustrates another exemplary method to profile an object shapein a touch and hover sensing device according to various embodiments. Inthe example of FIG. 11, a shape of a hovering object, e.g., a hand, canbe determined based on the hovering signal (1110). For example, thesensor locations that detected the hovering object can be used by anysuitable shape identification algorithm to determine the area and hencethe shape of the object. The centroid of the object can be calculated(1120). The centroid of the determined area and its corresponding sensorlocation can be calculated using any suitable centroid detectionalgorithm. A pointer can be set at the centroid to indicate an initialestimate of where the object is pointing (1130). The pointer locationcan be shifted from the centroid location to another sensor location ofthe object area that is more indicative of where the object is pointingand that is according to the shape of the object area (1140). Forexample, if the object shape has an extended portion toward the upperright of the device UI display, the pointer location can be shifted fromthe centroid to a sensor location in the upper right of the object area.A trajectory or some other extrapolation can be made from the shiftedpointer onto the UI display to estimate the pointed-to area (1150).

In some embodiments, the hovering signal in the determined object areacan be curve-fitted to determine the signal maximum, indicative of theportion of the object closest to the touch and hover sensing device andcorrespondingly where the object is pointing. Accordingly, the pointerlocation can be shifted from the centroid location to the sensorlocation corresponding to the signal maximum (1140). The shifted pointercan then be used to estimate the pointed-to area on the UI display(1150).

FIG. 12 illustrates another exemplary method to profile an object shapein a touch and hover sensing device according to various embodiments. Inthe example of FIG. 12, the motion of a hovering object, e.g., a hand,relative to the device can be used to determine where the object ispointing. Capacitance at times t and t+1 can be measured to detect ahovering object at those times (1210). The measurements can be comparedto estimate a direction of motion of the hovering object (1220). Forexample, sensor locations that detected the object can be used todetermine the object positions at times t and t+1. The shift in positionbetween times t and t+1 can then be used to determine the objectdirection of motion according to any suitable motion detectionalgorithm. The centroid of time t+1 measurement can be calculated(1230). For example, the sensor locations corresponding to the objectcan be used to determine the object area. The centroid of the objectarea and its corresponding sensor location can then be calculated usingany suitable centroid detection algorithm. A pointer can be set at thecentroid to indicate an initial estimate of where the object is pointing(1240). The pointer location can be shifted from the centroid locationin the determined direction of motion to another sensor location of theobject area that is more indicative of where the object is pointing andthat is according to the object's motion (1250). For example, if theobject is moving in an upward direction toward the top of the UIdisplay, the pointer location can be shifted in the upward directionfrom the centroid location to an uppermost sensor location of the objectarea. A trajectory or some other extrapolation can be made from theshifted pointer onto the device UI display to estimate the pointed-toarea (1260).

It is to be understood that other method are also possible to profile anobject shape according to the needs of the device.

Distance and Area Differentiation

A smaller object close to a sensing device and a larger object fartheraway from a sensing device can generate similar sensing signals suchthat it can be difficult to differentiate between them to determinetheir areas and/or distances from the device, which may adversely affectsubsequent device actions based on the signals. FIG. 13 illustrates suchan example. Here, smaller object 1314 having area a can be at distance dfrom touch and hover sensing device 1300, whereas larger object 1324having area A can be at distance D from the device, where A>a and D>d.However, hover signal 1312 for the smaller object 1314 can besubstantially the same as hover signal 1322 for the larger object 1324such that the differences in the respective distances d and D and areasa are A are not discernible.

FIG. 14 illustrates an exemplary touch and hover sensing device that candifferentiate between a small close object and a large distant objectaccording to various embodiments. In the example of FIG. 14, visualcapture device 1430 can be disposed at a position proximate to thesensor lines of touch and hover sensing device 1400 to capture image(s)and/or video of a hovering object. The captured image(s) and/or videocan then be used to determine the distance and area of the object. Thedistance of the object from the touch and hover sensing device can bedetermined according to the object and device positions in the capturedimage(s) and/or video using any suitable image/video object recognitionalgorithm. The area of the object can be determined according to thesize of the object in the captured image(s) and/or video using anysuitable image/video object recognition algorithm. Examples of visualcapture devices can include a still camera, a video camera, and thelike. In some embodiments, the capture device 1430 can be integratedwith the touch and hover sensing device 1400. In other embodiments, thecapture device 1430 can be separate and proximate to the touch and hoversensing device 1400.

FIG. 15 illustrates another exemplary touch and hover sensing devicethat can differentiate between a small close object and a large distantobject according to various embodiments. In the example of FIG. 15,detectors 1530 can be disposed at positions proximate to the sensorlines of touch and hover sensing device 1500 to detect a hoveringobject. The distance and area of the object can be determined accordingto various characteristics of the detectors' signal using any suitablesignal processing algorithm. Examples of the detectors can includesonar, infrared, optical, radio, and the like. In some embodiments, thedetectors 1530 can be integrated with the touch and hover sensing device1500. In other embodiments, the detectors 1530 can be separate andproximate to the touch and hover sensing device 1500.

In addition or alternative to using capture devices and detectors, thesensing signals can be used to differentiate between object distancesand areas, as described in FIG. 16.

FIG. 16 illustrates an exemplary method to differentiate between a smallclose object and a large distant object using sensing signals in a touchand hover sensing device according to various embodiments. In theexample of FIG. 16, capacitance at times t and t+1 can be measured todetect a hovering object at those times (1610). The measurements can beused to determine an object area (1620). For example, sensor locationsthat detected the object can be used to determine the object areas attimes t and t+1. The areas can be compared to determine the change inarea from time t to time t+1 (1630). Based on the change in area, thedistance of the object can be estimated (1640). One of the determinedobject area, e.g., at time t+1, and the estimated distance can be usedin subsequent device action, e.g., to select an element on a displayuser interface.

It is to be understood that other methods can be used to determineobject area and distance based on object sensing signals according tovarious embodiments.

Concurrent Touch and Hover

As described previously, an object touching a sensing device cangenerally produce a stronger signal than an object hovering over thedevice, such that the touch signal can mask or otherwise reducedetectability of the hover signal when they occur at the same time.Unlike the instance of FIG. 2, in this instance, the touch signal isintentional and desirable along with the hover signal. Therefore, thestronger touch signal masking the weaker hover signal can beproblematic. FIG. 17 illustrates such an example. Here, a user can grasptouch and hover sensing device 1700 with left hand 1712, using thumb1712-a to touch the device sensing area to provide a touch input, and atthe same time hover over the device with right hand 1714, using finger1714-b to point to areas on the device's UI display to provide a hoverinput, where the touch and hover inputs can work together to cause someaction. Because the thumb 1712-a touches the device 1700, the sensorsproximate to the thumb can generate a stronger signal, in some cases, asaturated signal. Whereas, because the finger 1714-b hovers above thedevice 1700, the sensors detecting the finger can generate a weakersignal, in some cases, a much weaker signal. Some adjustment to thedevice and/or the signals can be made to ensure that both the touchsignal and the hover signal are concurrently sensed.

An example application of concurrent touch and hover sensing can includeusing a thumb touch to select a button that changes to a particularoperating mode of the device while using a finger hover to select anaction to perform during that operating mode.

FIG. 18 illustrates an exemplary touch and hover sensing device toconcurrently sense a touching object and a hovering object according tovarious embodiments. In the example of FIG. 18, touch and hover sensingdevice 1800 can be partitioned (symbolically illustrated by brokenlines) into quadrants 1800-a, 1800-b, 1800-c, and 1800-d such that thesensing signals associated with the sensors in these quadrants can alsobe partitioned. The quadrants having stronger touch signals can bedetectible and separate from the quadrants having weaker hover signals,such that both the touch signals and the hover signals can be recoveredfor further processing. One or more of the quadrants where the touchsignal is more likely to occur can be designated as a touch quadrant.Similarly, one or more of the quadrants where the hover signal is morelikely to occur can be designated as a hover quadrant. Some quadrantscan be also designated dual quadrants where either touch or hoversignals are likely to occur. In this example, the left-most quadrant isdesignated as a touch quadrant because a user is more likely to graspthe device 1800 in this region and use the thumb of the grasping hand toprovide a touch input. The remaining quadrants are designated as thehover quadrants because a user is more likely to point to the device UIdisplay in these areas with a pointing hand or other object. In someembodiments, the partitioning can be performed in software and/orfirmware, where the quadrants can share sensor lines (not shown). Insome alternate embodiments, the partitioning can be done in hardware,where each quadrant can have separate sensor lines. To ensure that bothtouch and hover signals are properly sensed, the device 1800 can operatein a mutual capacitance mode, where the sensor lines measure mutualcapacitance. Alternatively, in some embodiments, the device 1800 canoperate in a self capacitance mode and employ similar approaches asdescribed above to detect but retain touch signals along with hoversignals.

Although the touch sensing device of FIG. 18 is partitioned intoquadrants, other numbers of partitions and/or configurations is alsoavailable, provided that each partition includes at least one edge ofthe device for connecting the sensor lines to drive and sense circuitry.

FIG. 19 illustrates an exemplary method to concurrently sense a touchingobject and a hovering object using the device of FIG. 18. In the exampleof FIG. 19, partitions can be designated as a touch partition, a hoverpartition, and/or a dual partition based on the likelihood of touch,hover, or both, respectively, occurring at that partition (1910). Mutualcapacitance can be measured in each partition (1920). Mutual capacitancesensing can more easily detect multiple objects, e.g., concurrenttouching and hovering objects, than self capacitance sensing in mostcases. A measurement in a designated touch partition that is indicativeof a detected object can be identified as a touch signal; whereas, ameasurement in a designated hover partition that is indicative of adetected object can be identified as a hover signal (1930). In the caseof a detected signal in a dual partition, in some embodiments, thesignal can be ignored or discarded as indeterminable. In otherembodiments, the magnitude of the signal can be compared to apredetermined threshold and deemed a touch signal if above the thresholdand a hover signal if at or below the threshold.

FIG. 20 illustrates another exemplary method to concurrently sense atouching object and a hovering object in a touch and hover sensingdevice according to various embodiments. Here the device can, but neednot, be partitioned. In the example of FIG. 20, while there is a touchat the device, a capacitance can be measured (2005). If the measurementsaturates the sensor lines, the measurement can be designated as a touchsaturation signal (2010). The device can be recalibrated based on thesaturated measurement such that subsequent touches at the device do notsaturate the sensor lines (2020). In some embodiments, to recalibratethe device, amplitudes of voltages driving the sensors can be reducedproportionate to the touch saturation signal so as to provide anunsaturated capacitance measurement. In some embodiments, to recalibratethe device, capacitance measurements can be reduced proportionate to thetouch saturation signal so as to provide an unsaturated capacitancemeasurement. During recalibration, care can be taken to balanceunsaturating a touch signal with appreciably reducing detectability of ahover signal as well as the overall signal-to-noise ration of thesignals. After the recalibration, subsequent touch signals can beunsaturated and detectible along with hover signals (2030).

It is to be understood that other methods for detecting concurrent hoverand touch events can also be used according to various embodiments.

Multi-Hover Detection

Detecting multiple hovering objects in a sensing device can be desirablefor device actions that need multiple inputs. FIG. 21 illustrates suchan example. Here, finger 2112-b can hover above one area of touch andhover sensing device 2100 while finger 2114-b can hover above anotherarea of the device. The device 2100 can then detect both fingers andgenerate hover signals for further processing.

FIG. 22 illustrates an exemplary graph of hover signals generated frommultiple hovering objects in a touch and hover sensing device accordingto various embodiments. In the example of FIG. 22, capacitancemeasurements along a sensor line can have peaks at sensor locationsproximate to the hovering objects. The measurements can be processed todetermine hover signals for the hovering objects as illustrated in FIG.23, for example. In some embodiments, to ensure that multiple hoversignals are properly sensed, the device can operate in a mutualcapacitance mode.

In the example of FIG. 23, capacitance can be measured (2310). Peaks inthe capacitance measurements can be identified, indicative of multiplehovering objects (2320). Any suitable peak detection algorithm can beused to identify the peaks. Some stray or small identified peaks can beignored or discarded to prevent false detections. Each identified peakcan be considered a hover signal of a hovering object and retained forfurther processing (2330).

In some embodiments, the touch and hover sensing device can bepartitioned into quadrants (or other partitions) such that multi-hovercan be realized in each quadrant, thereby increasing the number ofhovering objects that can be detected.

Signal Drift Compensation

When a sensing device experiences environmental changes, e.g., changesin ambient temperature, humidity, or pressure; operating changes, e.g.,component start-up, shutdown, prolonged operation, or noise; ormechanical changes, e.g., component shifts, expansion, or contraction,baseline capacitance of the device can change over time. Baselinecapacitance refers to the capacitance of the device when there is notouch or hover at the device. As a result, capacitance measurementsindicative of a touch or a hover at the device can similarly change.This is known as signal drift. Signal drift can adversely affect deviceaction, particularly when the action is responsive to a particularcapacitance measurement value or a particular capacitance range ofvalues. To compensate for signal drift, the baseline capacitance can bereset periodically to take into account any environmental, operating,mechanical, and other changes. The new baseline can then be applied to atouch or hover capacitance measurement to correct the measurement.

FIG. 24 illustrates an exemplary touch and hover sensing device that cancompensate for signal drift according to various embodiments. In theexample of FIG. 24, touch and hover sensing device 2400 can includetouch and hover sensor panel 2426 and cover plate 2428. The panel 2426can include sensor lines for generating capacitance measurementsindicative of a touching object and/or a hovering object. The plate 2428can be grounded and can cover the panel 2426 at a distance d from thepanel. The plate 2428 can be a device cover, for example, that a usercan pull down or slide over the panel 2426 after the user finishes withthe device 2400 temporarily. Alternatively, the plate 2428 can be oneside of a housing, for example, into which a user can place the device2400 for storage or transport after the user finished with the device2400 temporarily. During these periods of non-use, the device cancompensate for signal drift. For example, when the plate 2428 covers thepanel 2426, neither a touching nor hovering object is likely at thepanel (since the panel cannot be used with the plate in place) such thatany capacitance changes in the sensor lines at the panel can be solelyor substantially due to signal drift. Capacitance measurements can betaken and the panel 2426 can be calibrated with the measurements as thenew baseline. When the plate 2428 does not cover the panel 2426, atouching or hovering object is more likely at the panel such thatresetting the baseline capacitance can be suspended until the plate onceagain covers the panel.

FIG. 25 illustrates another exemplary touch and hover sensing devicethat can compensate for signal drift according to various embodiments.In the example of FIG. 25, touch and hover sensing device 2500 can be indocking station 2535. The docking station 2535 can be grounded. When thedevice 2500 is docked, neither a touching nor hovering object is likelyat the device such that any capacitance changes at the device 2500 canbe solely or substantially due to signal drift. Capacitance measurementscan be taken and the device 2500 can be calibrated with the measurementsas the new baseline. When the device 2500 is undocked, a touching orhovering object is more likely at the device such that resetting thebaseline capacitance can be suspended until the device is once againdocked.

In some embodiments, a touch and hover sensing device may not haveeither a cover or a docking station. In such embodiments, when a touchor hover is not detected, capacitance measurements can be taken and thedevice can be calibrated with the measurements as the new baseline. Thiscan be done when the device is idle for an extended period, when thedevice is in use but between touch or hover detections, or in someotherwise non-touch or non-hover circumstance.

Alternatively, rather than waiting until there is no touch or hover atthe device, a new baseline capacitance can be set during a touch orhover. FIG. 26 illustrates such an example. Here, while finger 2614-btouches touch and hover sensing device 2600 for a predetermined timeperiod without moving, capacitance measurements can be taken during thetime period to determine how the capacitance drifts over time. Theaverage of that drift can be the new baseline. Similarly, the fingerhovering without moving can be used to reset the baseline capacitance.

FIG. 27 illustrates an exemplary method to compensate for signal driftin a touch and hover sensing device according to various embodiments. Inthe example of FIG. 27, a determination can be made whether there is atouch or hover at the touch and hover sensing device (2710). In someembodiments, a user can input either an indication that there is notouch or hover or an indication to reset the baseline capacitance. Insome embodiments, the touch and hover sensing device can determine thatthere is no touch or hover at the device, for example, by detecting acover plate over the device (as in FIG. 24), the device in a dockingstation (as in FIG. 25), or some other device parameter indicative of anon-touch and non-hover condition.

If there is no touch or hover at the device, a determination can be madewhether the device is substantially stationary (2715). Typically asubstantially stationary device can be more desirable to reset thebaseline capacitance to avoid capacitance measurements being adverselyaffected by device motion. The device's motion can be determined usingany suitable motion detector or detection algorithm according to theneeds of the device. If the device is moving, resetting the baselinecapacitance can be suspended until conditions are more favorable. If thedevice is not moving, capacitance measurements can be taken tocompensate for signal drift (2720). A determination can be made whetherthe capacitance measurements indicate some unacceptable condition, e.g.,the measurements are either negative or drifting in a negative direction(2725). If so, resetting the baseline capacitance can be suspended untilconditions are more favorable. Otherwise, if the capacitancemeasurements are acceptable, the measurements can be set as the newbaseline capacitance for the device, thereby compensating for the signaldrift (2730).

If there is a touch or hover at the device, a determination can be madewhether the touching or hovering object is substantially stationary(2750). If not, the device is likely in operation or the object isshaking such that resetting the baseline can be suspended untilconditions are more favorable. If the touching or hovering object issubstantially stationary, the object is likely touching or hovering toreset the baseline capacitance (as in FIG. 26). The capacitance can bemeasured at the device (2755). A determination can be made whether thecapacitance measurements indicate some unacceptable condition, e.g., themeasurements are either negative or drifting in a negative direction(2760). If so, resetting the baseline capacitance can be suspended untilconditions are more favorable. Otherwise, if the capacitancemeasurements are acceptable, a determination can be made whether apredetermined time period associated with the baseline capacitance resethas expired (2765). If the time period has not expired, then additionalcapacitance measurements can be taken as long as the object remainsstationary (2750-2765). If the time period has expired, the capacitancemeasurements taken over the predetermined time period can be averaged(2770). The average can be set as the new baseline capacitance for thedevice, thereby compensating for the signal drift (2775).

In some embodiments, the user can manually input a new baselinecapacitance to compensate for the signal drift.

After the baseline capacitance has been reset, a capacitance can bemeasured indicative of either a touch or hover at the device (2780). Thenew baseline capacitance, compensated for signal drift, can besubtracted from the capacitance measurement to determine the capacitancechange as a result of the touch or hover (2785).

It is to be understood that other methods can also be used for resettingthe baseline capacitance to compensate for signal drift according to theneeds of the device.

Sensor Resistance Compensation

As described previously, due to resistance from touch and hover sensingdevice sensor lines' conductive material, the ability of a drive voltageto travel along a sensor line can be influenced by the drive voltage'sfrequency, where higher frequencies have more difficulty than lowerfrequencies. As a result, at higher frequency drive voltages, thesensors at the start of the sensor lines can see stronger drive voltagesthan sensors at the end of the sensor lines, thereby generating strongerelectric fields and subsequent touch and hover signals. At lowerfrequency drive voltages, the sensors all along the sensor lines can bedriven similarly, thereby generating acceptable electric fields andsubsequent touch and hover signals everywhere. While higher frequencydrive voltages are desirable, larger touch and hover sensing devices canhave difficulty driving all the sensors along longer sensor lines. Tocompensate for the sensor lines' resistance, various sensorconfigurations can be used as described below.

FIG. 28 illustrates an exemplary touch and hover sensing device that cancompensate for sensor resistance according to various embodiments. Inthe example of FIG. 28, adjacent sensor lines 2801-a through 2801-d oftouch and hover sensing device 2800 can be ganged together to lowersensor resistance. Ganging the sensor lines 2801-a and 2801-b caneffectively form single sensor line 2810-a, where the lines' individualresistances are now in parallel, thereby halving the total resistance ofthe ganged lines. The sensor lines 2801-c and 2801-d can be similarlyganged together to form single sensor line 2810-b. Ganging can alsolower the resolution of the device 2800 by combining two sensor linesinto one. Accordingly, lowering the resistance to produce strongersignals can be balanced against lowering the resolution of thosesignals. Hence, the amount of ganging can be determined so as to reducethe sensor lines' resistance while maintaining an appropriate sensingresolution.

In this example, the horizontal sensor lines are ganged together.However, it is to be understood that the vertical sensor lines can besimilarly ganged together according to the needs of the device.

FIG. 29 illustrates another exemplary touch and hover sensing devicethat can compensate for sensor resistance according to variousembodiments. In the example of FIG. 29, touch and hover sensing device2900 can dynamically gang sensor lines according to the distance ofhovering object 2914. The sensitivity of the device 2900 to the object2914 can be a function of the object's area and distance. When theobject 2914 is farther away at distance D, its area can be smaller suchthat the capacitance measurement at the device 2900 can be smaller. Ahigher sensor resolution can be preferred to properly sense the distantobject. Accordingly, the sensor lines 2901-a through 2901-d can remainseparate to provide a higher resolution. Conversely, when the object2914 is closer at distance d, its area can be larger such that thecapacitance measurement at the device 2900 can be larger. A lower sensorresolution can still properly sense the object. Accordingly, the sensorlines 2901-a and 2901-b can be ganged together as single sensor line2910-a and the sensor lines 2901-c and 2901-d can be ganged together assensor line 2910-b to realize lower sensor resistance. Ganging can beperformed for horizontal sensor lines, vertical sensor line, or both.

FIG. 30 illustrates another exemplary touch and hover sensing devicethat can compensate for sensor resistance according to variousembodiments. In the example of FIG. 30, drive voltage V₁ can be appliedto sensors along sensor lines 3001 of touch and hover sensing device3000 from both directions at the same time such that the distance thatthe voltage has to travel along the lines is halved, thereby reducingthe effects of the sensor resistance. In some embodiments, the drivevoltages can be applied to sensors along sensor lines 3002 from both topand bottom directions at the same time.

FIG. 31 illustrates another exemplary touch and hover sensing devicethat can compensate for sensor resistance according to variousembodiments. In the example of FIG. 31, touch and hover sensing device3100 can be physically partitioned (symbolically illustrated by thepartitioning lines) into quadrants 3100-a, 3100-b, 3100-c, and 3100-d,where each quadrant can have separate sensor lines 3101, 3102. Thepartitioning can shorten the sensor lines by half, such that theresistance along each line is halved, thereby reducing the effects ofsensor resistance.

Although the touch sensing device of FIG. 31 is partitioned intoquadrants, partitioning into other numbers of partitions and/orconfigurations is also available provided that each partition includesat least one edge of the device for connecting the sensor lines to driveand sense circuitry.

Sensitivity Variation Compensation

Touch or hover sensitivity can vary as a function of sensor location ina touch and hover sensing device. Sensor locations at the edges of thedevice can generally be less sensitive than sensor locations at thecenter of the device. FIG. 32 depicts an example of such sensitivityvariation as a function of sensor location in the device. Here, sensorsat the center of the device can have greater sensitivity than sensors atthe edges, where sensitivity decreases from the center to the edges.This means that an object hovering over the center of the device can besensed farther away than an object hovering over the edges of thedevice, with the sensing distance decreasing from a maximum at thecenter to a minimum at the edges. This can produce inconsistent hoversignals and, in some cases, missed hover signals at the device edges.Therefore, compensation for such sensitivity variation is desirable asdepicted in FIG. 33, where the sensors at various locations havesubstantially the same sensitivity.

To compensate for the sensitivity variation, a gain factor as a functionof the hover location can be applied to the capacitance measurement toensure consistent hover signals at any location on the device. FIG. 34illustrates an exemplary method to compensate for sensitivity variationin a touch and hover sensing device according to various embodiments. Inthe example of FIG. 34, capacitance can be measured at the deviceindicative of a hover at the device (3410). The sensor location of themeasurement can be determined (3420). Based on the determined location,a gain factor can be applied to the measurement to increase themeasurement as if it is at the center of the device in order tocompensate for any variation (3430). In some embodiments, the gainfactor can be multiplied with the measurement. The gain factor can becalculated as a ratio representing the amount that the sensitivity isreduced at the hover detected location from the sensitivity at thecenter of the device.

It is to be understood that other methods are also available tocompensation for sensitivity variations according to the needs of thedevice.

Touch and Hover Switching

As described previously, sensors formed from sensor lines of a touch andhover sensing device can sense both a touching object and a hoveringobject. In some embodiments, to sense a touching object, the sensors canbe configured based on mutual capacitance. In some embodiments, to sensea hovering object, the sensors can be configured based on selfcapacitance. Switching a sensor between a touch mode and a hover modecan be accomplished through software, firmware, or hardware.

FIG. 35 illustrates an exemplary touch and hover sensing device that canswitch between touch and hover modes according to various embodiments.In the example of FIG. 35, touch and hover sensing device 3500 can havesensor 3512 formed from sensor lines and coupled to touch and hovercontrol system 3507, which can control the sensor switching betweentouch and hover modes. The control system 3507 can include switch 3539,touch sensing circuit 3516, hover sensing circuit 3518, and controller3520. The switch 3539 can couple the sensor 3512 to either sensingcircuit 3516, 3518. In touch mode, the switch 3539 can couple the sensor3512 to the touch sensing circuit 3516 to process a touch signal. Inhover mode, the switch 3539 can couple the sensor 3512 to the hoversensing circuit 3518 to process a hover signal. The controller 3520 cancontrol the switch 3539 according to any suitable control scheme. Insome embodiments, the controller 3520 can switch between the two modesin response to a timer, where the switching occurs when the timerexpires. At that point, the timer can be reset to count down to the nextswitching. In some embodiments, the controller 3520 can switch betweenthe two modes in response to an input, such as a manual input from auser or a logical input from the device when a particular conditionoccurs.

The switch 3539 can have a substantial capacitance that can interferewith a touch signal or a hover signal from the sensor 3512. Theinterference can be more adverse in the hover signal where the hoversensing circuit can measure absolute capacitance. In contrast, theinterference can be less adverse, and in some cases advantageous, in thetouch signal where the touch sensing circuit can measure differentialcapacitance (or changes in capacitance). For example, in someembodiments, the switch capacitance can be about 20 pF, which can be thedynamic range of the signal. The switch capacitance can be offset withdevice components as illustrated in FIGS. 36 and 37 below.

FIG. 36 illustrates another exemplary touch and hover sensing devicethat can switch between touch and hover modes, the device having a gainamplifier for offsetting a capacitance that can be introduced into thedevice by a switch used to change between the two modes. In the exampleof FIG. 36, gain amplifier 3644 of hover sensing circuit 3618 canreceive on one pin a hover sensing signal, indicative of a hover atsensor 3612 and of a capacitance at switch 3639, and can receive on theother pin a reference signal that the amplifier can subtract from thehover sensing signal. The resulting output from the gain amplifier 3644can be an unsaturated, corrected hover signal of the hover measured atthe sensor 3612.

FIG. 37 illustrates another exemplary touch and hover sensing devicethat can switch between touch and hover modes having a capacitor foroffsetting a capacitance that can be introduced into the device by aswitch used to change between the two modes. In the example of FIG. 37,capacitor 3756 can be located between sensor 3712 and switch 3739. Thecapacitor's capacitance can be in series with the switch capacitance,thereby effectively reducing the total capacitance experienced by hoversensing circuit 3718 by half. The resulting signal to the hover sensingcircuit 3718 can be unsaturated with a reduced sensitivity.

As an alternative to a switch for switching between touch and hovermodes, logic can be used to switch between the modes. FIG. 38illustrates an exemplary touch and hover sensing device that can switchbetween touch and hover modes according to various embodiments. In theexample of FIG. 38, touch and hover sensing device 3800 can have sensor3812 formed by sensor lines and coupled to touch and hover controlsystem 3807, which can control the sensor switching between touch andhover modes. The control system 3807 can include touch sensing circuit3816, hover sensing circuit 3818, and controller 3820. The hover sensingcircuit 3818 and the touch sensing circuit 3816 can be connectedtogether on a line coupled to the sensor 3812. The controller 3820 candisable and enable the sensing circuits 3816, 3818 according to themode. In touch mode, the controller 3820 can send an enable signal tothe touch sensing circuit 3816 and a disable signal to the hover sensingcircuit 3818, such that the touch sensing circuit can process the sensorsignal and the hover sensing circuit can float. In hover mode, thecontroller 3820 can send a disable signal to the touch sensing circuit3816 and an enable signal to the hover sensing circuit 3818, such thatthe hover sensing circuit can process the sensor signal and the touchsensing circuit can float. The controller 3820 can generate and send thedisable and enable signals according to any suitable control scheme. Insome embodiments, the controller 3820 can generate and send the disableand enable signals upon expiration of a timer. The controller 3820 canreset the timer upon sending the signals. In some embodiments, thecontroller 3820 can generate and send the disable and enable signals inresponse to a particular condition at the device, e.g., according to theproximity of an object to the sensor 3812.

There can be parasitic capacitance on the lines connecting the touchsensing circuit 3816 and the hover sensing circuit 3818 together whichcan interfere with the touch signal and the hover signal from the sensor3812. As described previously, the interference can be more adverse inthe hover signal than the touch signal. In one embodiment, to reduce theeffects of the parasitic capacitance on the hover signal,characteristics of the touch sensing circuit and the hover sensingcircuit can be adjusted so as to provide a high impedance state througha resistor at the touch sensing circuit to force the voltage path fromthe sensor to stay at the hover sensing circuit and to impede theparasitic capacitance at the touch sensing circuit from interfering.Other solutions are also available for reducing parasitic capacitance.

FIG. 39 illustrates an exemplary method to switch between touch andhover modes of a touch and hover sensing device based on proximity of anobject to the device according to various embodiments. This method canbe implemented in software, firmware, or hardware according to the needsof the device either to cause a switch to couple a sensor to anappropriate sensing circuit based on the mode, as in FIGS. 35 through 37or to enable or disable sensing circuits based on the mode, as in FIG.38. In the example of FIG. 39, a controller of a touch sensing devicecan switch to hover mode so that a hover sensing circuit of the devicecan measure a hover capacitance at sensors of the device (3910). In someembodiments, the controller can send a control signal to actuate aswitch to couple with the hover sensing circuit. In some embodiments,the controller can send an enable signal to the hover sensing circuitand a disable signal to the touch sensing circuit.

A determination can be made whether an object is far away from thedevice based on the hover measurement (3920). To perform thedetermination, the hover measurement can be compared to a thresholdhover measurement. If the hover measurement is at or lower than thehover threshold, the object can be determined to be far away. If thehover measurement is higher than the hover threshold, the object can bedetermined to be close.

If the object is determined to be far away, the device can continue inhover mode, repeating a hover capacitance measurement (3910) anddetermining whether the object is still far away (3920) until the hovermeasurement exceeds the hover threshold, indicating that the object istouching or almost touching the device.

If however the object is determined to be close, the controller canswitch to touch mode so that a touch sensing circuit of the device canmeasure a touch capacitance at the sensors (3930). In some embodiments,the controller can send a control signal to actuate a switch to couplewith the touch sensing circuit. In some embodiments, the controller cansend an enable signal to the touch sensing circuit and a disable signalto the hover sensing circuit.

A determination can be made whether an object is touching the devicebased on the touch measurement (3940). To perform the determination, thetouch measurement can be compared to a threshold touch measurement. Ifthe touch measurement is at or higher than the touch threshold, theobject can be determined to be touching the device. If the touchmeasurement is lower than the touch threshold, the object can bedetermined not to be touching the device.

If the object is determined to be touching the device, the device cancontinue in touch mode, repeating a touch capacitance measurement (3930)and determining whether the object is still touching the device (3940)until the touch measurement falls below the touch threshold, indicatingthere is no longer a touch on the device.

If however the object is determined not to be touching the device, themeasurement can be considered ambiguous since it is between thethreshold hover measurement and the threshold touch measurement. Assuch, the device can switch between the two modes until such time thatthe measurement satisfies either of the thresholds. Accordingly, thecontroller can switch back to hover mode and the method can repeat(3910) through (3940).

It is to be understood that the method of FIG. 39 is not limited to thatshown, but can include additional and/or other actions according to theneeds of the device.

FIG. 40 illustrates another exemplary method to switch between touch andhover modes of a touch and hover sensing device based on a timeraccording to various embodiments. This method can be implemented insoftware, firmware, or hardware according to the needs of the deviceeither to cause a switch to couple a sensor to an appropriate sensingcircuit based on the mode, as in FIGS. 35 through 37 or to enable ordisable sensing circuits based on the mode, as in FIG. 38. In theexample of FIG. 40, a controller of a touch and hover sensing device candetermine whether a timer has expired (4010). If the timer has notexpired, the device can continue in the current mode (4020). If in atouch mode, sensors of the device can be coupled to a touch sensingcircuit. If in a hover mode, the sensors can be coupled to a hoversensing circuit.

If the timer has expired, the controller can reset the timer (4030). Thecontroller can switch to another mode (4040). If the device was in thetouch mode, the device can switch to the hover mode. In someembodiments, to perform the switching, the controller can send a controlsignal to actuate a switch to decouple from a touch sensing circuit andto couple to a hover sensing circuit. In other embodiments, to performthe switching, the controller can send an enable signal to the hoversensing circuit and a disable signal to the touch sensing circuit. If,however, the device was in the hover mode, the device can switch to thetouch mode. In some embodiments, to perform the switching, thecontroller can send a control signal to actuate a switch to decouplefrom the hover sensing circuit and to couple to the touch sensingcircuit. In other embodiments, to perform the switching, the controllercan send an enable signal to the touch sensing circuit and a disablesignal to the hover sensing circuit.

After switching to another mode, the controller can repeat the method(4010) through (4040), checking for expiration of the timer and, uponexpiration, resetting the timer and switching to a different mode.

It is to be understood that the method of FIG. 40 is not limited to thatshown, but can include additional and/or other actions according to theneeds of the device.

In touch and hover switching, some or all of the sensors can be switchedbetween the two modes. For example, in some embodiments, a portion ofthe sensors can be switched to hover mode to couple to the hover sensingcircuit and a portion of the sensors can be switched to touch mode tocouple to the touch sensing circuit. This can implement panelpartitioning as described previously. In other embodiments, all of thesensor can be switched to the hover mode to couple to the hover sensingcircuit or to the touch mode to couple to the touch sensing circuit.

Display Integration

In some embodiments, a touch and hover sensing device can integrate adisplay device with the touch and hover sensing panel, where the displaycan provide a graphical user interface with various graphics selectablevia a touch or hover signal from the panel to cause the device toperform actions associated with the selected graphics. Because of itsproximity to the panel, the display can interfere with the touch orhover signals generated by the panel to introduce noise, decrease touchor hover sensitivity, or otherwise adversely affect the signals. Thiscan then cause unintended device action.

FIG. 41 illustrates an exemplary touch and hover sensing device that canreduce interference between the device display and the device touch andhover sensing panel according to various embodiments. In the example ofFIG. 41, grounding shield 4138 can be disposed between touch and hoversensing panel 4126 and display 4128. The grounding shield 4138 can helpelectrically isolate the panel 4126 from the display 4128 to reduceundesirable effects from the display to the panel.

FIG. 42 illustrates another exemplary touch and hover sensing devicethat can reduce interference between the device display and the devicetouch and hover sensing panel according to various embodiments. In theexample of FIG. 42, touch and hover sensing panel 4226 and display 4228can be spaced apart by optimal distance d. The optimal distance can bethe distance at which effects from the display to the panel aresubstantially reduced or eliminated such that the touch and hoversignals are minimally affected. In some embodiments, the optimaldistance d=1 mm. Here, the optimal distance d can substantially reduceor eliminate the need for a grounding shield.

Exemplary Touch and Hover Sensing Devices

FIG. 43 illustrates an exemplary computing system 4300 that can havetouch and hover sensing according to various embodiments describedherein. In the example of FIG. 43, computing system 4300 can includetouch and hover control system 4306. The touch and hover control system4306 can be a single application specific integrated circuit (ASIC) thatcan include one or more processor subsystems 4302, which can include oneor more main processors, such as ARM968 processors or other processorswith similar functionality and capabilities. However, in otherembodiments, the processor functionality can be implemented instead bydedicated logic, such as a state machine. The processor subsystems 4302can also include peripherals (not shown) such as random access memory(RAM) or other types of memory or storage, watchdog timers and the like.The touch and hover control system 4306 can also include receive section4307 for receiving signals, such as touch and hover signals 4303 of oneor more sense channels (not shown), other signals from other sensorssuch as sensor 4311, etc. The receive section 4307 can include a touchsensing circuit, a hover sensing circuit, and a switching mechanism toswitch between the sensing circuits according to the received touch andhover signals 4303. The touch and hover control system 4306 can alsoinclude demodulation section 4309 such as a multistage vectordemodulation engine, panel scan logic 4310, and transmit section 4314for transmitting stimulation signals 4316 to touch and hover sensorpanel 4324 to drive the panel. The panel scan logic 4310 can access RAM4312, autonomously read data from the sense channels, and providecontrol for the sense channels. In addition, the panel scan logic 4310can control the transmit section 4314 to generate the stimulationsignals 4316 at various frequencies and phases that can be selectivelyapplied to horizontal lines and/or vertical lines of the sensor panel4324.

The touch and hover control system 4306 can also include charge pump4315, which can be used to generate the supply voltage for the transmitsection 4314. The stimulation signals 4316 can have amplitudes higherthan the maximum voltage by cascading two charge store devices, e.g.,capacitors, together to form the charge pump 4315. Therefore, thestimulus voltage can be higher (e.g., 43V) than the voltage level asingle capacitor can handle (e.g., 3.6 V). Although FIG. 43 shows thecharge pump 4315 separate from the transmit section 4314, the chargepump can be part of the transmit section.

Touch and hover sensor panel 4324 can include a capacitive sensingmedium having sensors for detecting a touch event or a hover event atthe panel. The sensors can be formed from a transparent conductivemedium such as indium tin oxide (ITO) or antimony tin oxide (ATO),although other transparent and non-transparent materials such as coppercan also be used. Each sensor can represent a capacitive sensing nodeand can be viewed as picture element (pixel) 4326, which can beparticularly useful when the sensor panel 4324 is viewed as capturing an“image” of touch or hover. (In other words, after the touch and hovercontrol system 4306 has determined whether a touch event or a hoverevent has been detected at each sensor in the sensor panel, the patternof sensors in the panel at which a touch event or a hover event occurredcan be viewed as an “image” of touch or hover (e.g. a pattern of anobject touching or hovering over the panel).)

Computing system 4300 can also include host processor 4328 for receivingoutputs from the processor subsystems 4302 and performing actions basedon the outputs that can include, but are not limited to, moving anobject such as a cursor or pointer, scrolling or panning, adjustingcontrol settings, opening a file or document, viewing a menu, making aselection, executing instructions, operating a peripheral device coupledto the host device, answering a telephone call, placing a telephonecall, terminating a telephone call, changing the volume or audiosettings, storing information related to telephone communications suchas addresses, frequently dialed numbers, received calls, missed calls,logging onto a computer or a computer network, permitting authorizedindividuals access to restricted areas of the computer or computernetwork, loading a user profile associated with a user's preferredarrangement of the computer desktop, permitting access to web content,launching a particular program, encrypting or decoding a message, and/orthe like. The host processor 4328 can also perform additional functionsthat may not be related to panel processing, and can be coupled toprogram storage 4332 and display device 4330 such as an LCD display forproviding a UI to a user of the device. In some embodiments, the hostprocessor 4328 can be a separate component from the touch and hovercontrol system 4306, as shown. In other embodiments, the host processor4328 can be included as part of the touch and hover control system 4306.In still other embodiments, the functions of the host processor 4328 canbe performed by the processor subsystem 4302 and/or distributed amongother components of the touch and hover control system 4306. The displaydevice 4330 together with the touch and hover sensor panel 4324, whenlocated partially or entirely under the sensor panel or when integratedwith the sensor panel, can form a touch sensitive device such as a touchscreen.

Note that one or more of the functions described above can be performed,for example, by firmware stored in memory (e.g., one of the peripherals)and executed by the processor subsystem 4302, or stored in the programstorage 4332 and executed by the host processor 4328. The firmware canalso be stored and/or transported within any computer readable storagemedium for use by or in connection with an instruction execution system,apparatus, or device, such as a computer-based system,processor-containing system, or other system that can fetch theinstructions from the instruction execution system, apparatus, or deviceand execute the instructions. In the context of this document, a“computer readable storage medium” can be any medium that can contain orstore the program for use by or in connection with the instructionexecution system, apparatus, or device. The computer readable storagemedium can include, but is not limited to, an electronic, magnetic,optical, electromagnetic, infrared, or semiconductor system, apparatusor device, a portable computer diskette (magnetic), a random accessmemory (RAM) (magnetic), a read-only memory (ROM) (magnetic), anerasable programmable read-only memory (EPROM) (magnetic), a portableoptical disc such a CD, CD-R, CD-RW, DVD, DVD-R, or DVD-RW, or flashmemory such as compact flash cards, secured digital cards, USB memorydevices, memory sticks, and the like.

The firmware can also be propagated within any transport medium for useby or in connection with an instruction execution system, apparatus, ordevice, such as a computer-based system, processor-containing system, orother system that can fetch the instructions from the instructionexecution system, apparatus, or device and execute the instructions. Inthe context of this document, a “transport medium” can be any mediumthat can communicate, propagate or transport the program for use by orin connection with the instruction execution system, apparatus, ordevice. The transport medium can include, but is not limited to, anelectronic, magnetic, optical, electromagnetic or infrared wired orwireless propagation medium.

FIG. 44 illustrates an exemplary mobile telephone 4400 that can includea display 4436 and a touch and hover sensor panel 4424 according tovarious embodiments.

FIG. 45 illustrates an exemplary digital media player 4500 that caninclude a display 4536 and a touch and hover sensor panel 4524 accordingto various embodiments.

FIG. 46 illustrates an exemplary personal computer 4600 that can includea touch and hover sensitive display 4636 and a touch and hover sensorpanel (trackpad) 4624 according to various embodiments.

The mobile telephone, media player, and personal computer of FIGS. 44through 46 can advantageously provide improved touch and hover sensingaccording to various embodiments.

In the examples above, a capacitance measurement can be a measure of acapacitance at a particular time, i.e., an absolute capacitance, or ameasure of a capacitance difference over a particular time period, i.e.,a change in capacitance. Accordingly, in some embodiments, touch eventsor hover events can be detected by a measurement of absolute capacitanceat sensing lines of a touch and hover sensing device. In otherembodiments, touch events or hover events can be detected by ameasurement of a change in capacitance at sensing lines of a touch andhover sensing device. In still other embodiments, touch events or hoverevents can be detected by a combination of measurements of absolutecapacitance and a change in capacitance at sensing lines of a touch andhover sensing device. The particular measurement can be determinedaccording to the particular function, e.g., signal compensation, signaldetection, etc., being performed by the device.

Although embodiments have been fully described with reference to theaccompanying drawings, it is to be noted that various changes andmodifications will become apparent to those skilled in the art. Suchchanges and modifications are to be understood as being included withinthe scope of the various embodiments as defined by the appended claims.

What is claimed is:
 1. A capacitive sensing device comprising: a controlsystem configured to control switching between a mutual capacitance modeand a self-capacitance mode, wherein: the control system comprises: amutual capacitance sensing circuit configured to measure mutualcapacitance at the sensing device, a self-capacitance sensing circuitconfigured to measure self-capacitance at the sensing device, and aswitching mechanism configured to couple at least one sensor capable ofdetecting mutual capacitance or self-capacitance to either the mutualcapacitance sensing circuit or the self-capacitance sensing circuit, theswitching mechanism coupling the at least one sensor to the mutualcapacitance sensing circuit during the mutual capacitance mode and tothe self-capacitance sensing circuit during the self-capacitance mode,and the control system is configured to: measure a first capacitance atthe sensing device using the at least one sensor, the first capacitanceindicative of an object proximate to the device, in accordance with adetermination that the first capacitance is greater than a firstthreshold associated with the mutual capacitance mode, operate thesensing device in the mutual capacitance mode, in accordance with adetermination that the first capacitance is less than a second thresholdassociated with the self-capacitance mode, operate the sensing device inthe self-capacitance mode, and in accordance with a determination thatthe first capacitance is less than the first threshold and greater thanthe second threshold, alternate operation of the sensing device betweenthe mutual capacitance mode and the self-capacitance mode.
 2. The deviceof claim 1, wherein the switching mechanism is a switch.
 3. The deviceof claim 1, wherein the control system further comprises a controllerconfigured to control the switching mechanism, the controller sending acontrol signal to the switching mechanism to actuate the switchingmechanism.
 4. The device of claim 1, wherein the self-capacitancesensing circuit comprises a gain amplifier for sensing theself-capacitance at the sensing device, the gain amplifier coupling tothe at least one sensor through a first connection to receive theself-capacitance measurement, and to a reference voltage source througha second connection to receive a reference signal, the gain amplifiersubtracting the reference signal from the self-capacitance measurementso as to output a signal compensated for parasitic capacitance at theswitching mechanism.
 5. The device of claim 1, wherein the controlsystem further comprises a capacitor disposed between the at least onesensor and the switching mechanism so as to compensate theself-capacitance measurement at the sensing device for parasiticcapacitance at the switching mechanism.
 6. The device of claim 1,wherein the switching mechanism is a controller configured to sendcontrol signals to the mutual capacitance sensing circuit and theself-capacitance sensing circuit to switch between the sensing circuits.7. The device of claim 6, wherein, during the mutual capacitance mode,the controller sends an enable signal to the mutual capacitance sensingcircuit to enable the mutual capacitance sensing circuit and a disablesignal to the self-capacitance sensing circuit to disable theself-capacitance sensing circuit, and, during the self-capacitance mode,the controller sends a disable signal to the mutual capacitance sensingcircuit to disable the mutual capacitance sensing circuit and an enablesignal to the self-capacitance sensing circuit to enable theself-capacitance sensing circuit.
 8. The device of claim 1, wherein thefirst and second thresholds are indicative of relative distances fromthe sensing device of the object proximate to the device.
 9. The deviceof claim 1, wherein the control system measures self-capacitance at theat least one sensor during the self-capacitance mode.
 10. The device ofclaim 1, wherein the control system measures mutual capacitance at theat least one sensor during the mutual capacitance mode.
 11. The deviceof claim 1, wherein the first threshold is indicative of an objecttouching the sensing device and the second threshold is indicative of anobject hovering over the sensing device.
 12. A method of switchingbetween a mutual capacitance sensing mode and a self-capacitance sensingmode of a sensing device, the method comprising: measuring a firstcapacitance at the sensing device using at least one sensor, the firstcapacitance indicative of an object proximate to the device, and the atleast one sensor configured to be used in both the mutual capacitanceand self-capacitance sensing modes; in accordance with a determinationthat the first capacitance is greater than a first threshold associatedwith the mutual capacitance sensing mode, operating the sensing devicein the mutual capacitance sensing mode, in accordance with adetermination that the first capacitance is less than a second thresholdassociated with the self-capacitance sensing mode, operating the sensingdevice in the self-capacitance sensing mode, and in accordance with adetermination that the first capacitance is less than the firstthreshold and greater than the second threshold, alternating operationof the sensing device between the mutual capacitance sensing mode andthe self-capacitance sensing mode.
 13. The method of claim 12, whereinthe first threshold is indicative of an object touching the sensingdevice and the second threshold is indicative of an object hovering overthe sensing device.
 14. The method of claim 12, wherein the firstthreshold is higher than the second threshold.
 15. The method of claim12, wherein the mutual capacitance sensing mode is a touch mode todetect an object touching the device.
 16. The method of claim 12,wherein the self-capacitance sensing mode is a hover mode to detect anobject hovering over the device.
 17. A capacitive sensing devicecomprising: a sensing panel having multiple sensors, each capable ofdetecting mutual capacitance or self-capacitance and configured todetect one or more objects proximate to the panel; and a control systemconfigured to measure capacitance associated with the proximate objectsand to switch the sensors between a mutual capacitance detection modeand a self-capacitance detection mode, wherein the control system isconfigured to: measure a first capacitance at the sensing device usingthe sensors, the first capacitance indicative of the one or more objectsproximate to the panel, in accordance with a determination that thefirst capacitance is greater than a first threshold associated with themutual capacitance detection mode, operate the sensing device in themutual capacitance detection mode, in accordance with a determinationthat the first capacitance is less than a second threshold associatedwith the self-capacitance detection mode, operate the sensing device inthe self-capacitance detection mode, and in accordance with adetermination that the first capacitance is less than the firstthreshold and greater than the second threshold, alternate operation ofthe sensing device between the mutual capacitance detection mode and theself-capacitance detection mode.
 18. The device of claim 17, wherein thecontrol system switches a portion of the sensors to the mutualcapacitance detection mode and another portion of the sensors to theself-capacitance detection mode so as to partition the panel toconcurrently detect mutual capacitance and self-capacitance at thepanel.
 19. The device of claim 17, further comprising a displayconfigured to display graphical information to select in response to theone or more objects proximate to the panel.
 20. The device of claim 17incorporated into at least one of a mobile phone, a digital mediaplayer, or a computer.
 21. The device of claim 17, wherein the firstthreshold is indicative of an object touching the sensing device and thesecond threshold is indicative of an object hovering over the sensingdevice.